S-Class (W140) 1991-1999: 300 SD, S 350TD, 300 SE 2.8, S280, 300 SE 3.2, 300 SEL 3.2, S320, S320L, 400 SE, S420, 400 SEL, S420L, 500 SE, S500, 500 SEL, S500L, 600 SE, S600, 600 SEL, S600L, 500 SEC, 600 SEC

exposed elec circuit to battery charger

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Old Jun 9, 2019 | 06:25 PM
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w140 s500
exposed elec circuit to battery charger

It all started yesterday when I reset the soft close pump by pulling the fuse. Soft close has not been working and I have been limping by without it. So I found out yesterday when the soft close pump was operating that it somehow was draining the battery. I figure it is leaking and continuing to run the pump. So I connected my Sears Brand 10 amp charger to the battery while still connected to the w140 and later on, to make matters worse, I inserted the key and turned on the accessorys while the charger was still charging the battery. When I turned on the key to accessory I heard a somewhat screeching fan noise coming from somewhere behind the passenger side dash and I turned the key off and removed it. (But not before I tried to start the car but nothing, no cranking and no clicking.) Thoroughly shaken by my ability to make big mistakes I left the car alone, disconnected the charger and tried to sleep.
The battery was completely dead this morning so I removed the battery and connected the battery to the charger and it should take between 12 to 24 hours to fully charge. I will check at 12 hours.
I am worried that I did serious damage to the electrical system of the w140.
If I were able to get back to where I was before charging, I would pull the fuse for the soft close pump and move forward with a repair this week (go in and at lease look and listen to the pump operate). But now I have a bigger potential problem.
Tomorrow I install a fully charged battery and pray.
What else should I do?

Background on car. 1995 s500 w140 one owner car with 102k mi. I have had if for one year. It is reliable and mostly working well (until I zapped it.)
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Old Jun 11, 2019 | 06:48 PM
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w140 s500
So, it looks like there was no serious damage by my charging the w140 battery with a sears 10 amp charger while the battery was still connected to the car (exposed to the cars open circuit).Great news. I discovered this when I charged the battery unattached to the car to what I believe to be fully charged. I tested it and the multi meter and it read 15 so I think that was a correct 15 amp output. The car started fine with no god awful screaking fan noises from the dashboard. So I am happy that all I have to deal with now is my non latching trunk and soft close (non) function and maybe if I need a new battery because these cars seem to need a very high functioning battery and I may have damaged it because of the complete draining and fast recharge. The following morning the battery had run down again. So i am working through it. Sorry for the false alarm after my low voltage scare. I love my car and I was sure that I blew it up.

New question: I tried to lock the truck manually by using the proceedure in owners manual where I use the button inside the trunk lid and by pushing the lock device in. this did not work. no clicking no movement at all. I may be doing something wrong but it does not seem so. can anyone help. these truck mechanism seem to be ground zero on these cars. Thanks.
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